https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106808
Bug ID: 106808
Summary: std::string_view range concept requirement causes
compile error with Boost.Filesystem
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: andysem at mail dot ru
Target Milestone: ---
Created attachment 53528
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53528&action=edit
Preprocessed code of the reproducer.
The following code fails to compile in C++23 mode:
#include <boost/filesystem/path.hpp>
int main()
{
boost::filesystem::path p = "foo";
boost::filesystem::path p2 = p;
}
$ g++ -std=c++23 -I. -c fs_concepts_issue.cpp -o fs_concepts_issue.o
In file included from /usr/include/c++/11/bits/stl_iterator_base_types.h:71,
from /usr/include/c++/11/bits/stl_algobase.h:65,
from /usr/include/c++/11/bits/char_traits.h:39,
from /usr/include/c++/11/string:40,
from /usr/include/c++/11/bits/locale_classes.h:40,
from /usr/include/c++/11/locale:39,
from ./boost/filesystem/detail/path_traits.hpp:18,
from ./boost/filesystem/path.hpp:21,
from fs_concepts_issue.cpp:1:
/usr/include/c++/11/bits/ranges_base.h: In substitution of ‘template<class _Tp>
requires (__maybe_borrowed_range<_Tp>) && ((is_array_v<typename
std::remove_reference<_Tp>::type>) || (__member_begin<_Tp>) ||
(__adl_begin<_Tp>)) constexpr auto
std::ranges::__cust_access::_Begin::operator()(_Tp&&) const [with _Tp = const
boost::filesystem::path&]’:
/usr/include/c++/11/bits/ranges_base.h:576:15: required by substitution of
‘template<class _Range, class _DRange> requires !(is_same_v<_DRange,
std::basic_string_view>) && (contiguous_range<_Range>) && (sized_range<_Range>)
&& (is_same_v<typename std::__detail::__iter_traits_impl<typename
std::remove_cvref<decltype(std::ranges::__cust_access::__begin((declval<_Range&>)()))>::type,
std::indirectly_readable_traits<typename
std::remove_cvref<decltype(std::ranges::__cust_access::__begin((declval<_Range&>)()))>::type>
>::__iter_traits<typename
std::remove_cvref<decltype(std::ranges::__cust_access::__begin((declval<_Range&>)()))>::type,
std::indirectly_readable_traits<typename
std::remove_cvref<decltype(std::ranges::__cust_access::__begin((declval<_Range&>)()))>::type>
>::value_type, _CharT>) && !(is_convertible_v<_Range, const _CharT*>) &&
!requires(_DRange& __d) {__d->__conv_op ();} && (!requires{typename
_DRange::traits_type;} || (is_same_v<typename _DRange::traits_type, _Traits>))
constexpr std::basic_string_view<wchar_t>::basic_string_view(_Range&&) [with
_Range = wchar_t; _DRange = std::char_traits<wchar_t>]’
./boost/filesystem/detail/path_traits.hpp:514:93: required from ‘constexpr
const bool
boost::filesystem::detail::path_traits::is_convertible_to_std_string_view<boost::filesystem::path>::value’
./boost/type_traits/disjunction.hpp:31:27: required from ‘struct
boost::disjunction<boost::filesystem::detail::path_traits::is_convertible_to_std_string_view<boost::filesystem::path>,
boost::filesystem::detail::path_traits::is_convertible_to_path_source_non_std_string_view<boost::filesystem::path>
>’
./boost/filesystem/detail/path_traits.hpp:537:8: required from ‘struct
boost::filesystem::detail::path_traits::is_convertible_to_path_source<boost::filesystem::path>’
./boost/type_traits/disjunction.hpp:26:8: required from ‘struct
boost::disjunction<boost::filesystem::detail::path_traits::is_convertible_to_path_source<boost::filesystem::path>
>’
./boost/type_traits/disjunction.hpp:30:8: required from ‘struct
boost::disjunction<boost::filesystem::detail::path_traits::is_path_source<boost::filesystem::path>,
boost::filesystem::detail::path_traits::is_convertible_to_path_source<boost::filesystem::path>
>’
./boost/type_traits/conjunction.hpp:31:27: required from ‘struct
boost::conjunction<boost::disjunction<boost::filesystem::detail::path_traits::is_path_source<boost::filesystem::path>,
boost::filesystem::detail::path_traits::is_convertible_to_path_source<boost::filesystem::path>
>,
boost::negation<boost::filesystem::detail::path_traits::is_native_path_source<boost::filesystem::path>
> >’
./boost/filesystem/path.hpp:249:9: required by substitution of
‘template<class Source, class> boost::filesystem::path::path(const Source&)
[with Source = boost::filesystem::path; <template-parameter-1-2> = <missing>]’
fs_concepts_issue.cpp:6:34: required from here
/usr/include/c++/11/bits/iterator_concepts.h:942:15: required for the
satisfaction of ‘__member_begin<_Tp>’ [with _Tp = const
boost::filesystem::path&]
/usr/include/c++/11/bits/iterator_concepts.h:942:32: in requirements with
‘_Tp& __t’ [with _Tp = const boost::filesystem::path&]
/usr/include/c++/11/bits/iterator_concepts.h:942:32: error: satisfaction value
of atomic constraint ‘requires(_Tp& __t)
{{std::ranges::__cust_access::__decay_copy(__t->begin())} -> decltype(auto)
[requires std::input_or_output_iterator<<placeholder>, >];} [with _Tp = const
boost::filesystem::path&]’ changed from ‘false’ to ‘true’
942 | concept __member_begin = requires(_Tp& __t)
| ^~~~~~~~~~~~~~~~~~
943 | {
| ~
944 | { __decay_copy(__t.begin()) } -> input_or_output_iterator;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
945 | };
| ~
In file included from /usr/include/c++/11/string_view:48,
from /usr/include/c++/11/bits/basic_string.h:48,
from /usr/include/c++/11/string:55,
from /usr/include/c++/11/bits/locale_classes.h:40,
from /usr/include/c++/11/locale:39,
from ./boost/filesystem/detail/path_traits.hpp:18,
from ./boost/filesystem/path.hpp:21,
from fs_concepts_issue.cpp:1:
/usr/include/c++/11/bits/ranges_base.h:576:22: note: satisfaction value first
evaluated to ‘false’ from here
576 | ranges::begin(__t);
| ~~~~~~~~~~~~~^~~~~
$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/11/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
11.2.0-19ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-11
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-11-gBFGDP/gcc-11-11.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-11-gBFGDP/gcc-11-11.2.0/debian/tmp-gcn/usr
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
--with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (Ubuntu 11.2.0-19ubuntu1)
This is with Boost.Filesystem revision
5d4c1caaab65012f939ffa118cc1f36d34198c0b.
The code compiles with -std=c++20. It also compiles with MSVC 14.3
/std:c++latest
Sorry, I have little knowledge about concepts and I couldn't reduce the repro
further. I've attached the preprocessed code.
